The document discusses turbulence near walls and different approaches to modeling it in computational fluid dynamics (CFD). It explains that the boundary layer can be divided into different zones, and CFD requires different considerations depending on whether the viscous sub-layer is solved, the log-law layer is modeled, or the whole boundary layer is solved. It also discusses the use of non-dimensional variables to characterize the boundary layer and describes different near-wall treatments in CFD, including resolving the boundary layer with fine meshes or using wall functions with coarser meshes.
The document discusses reactive flow modeling using the eddy dissipation model (EDM) in ANSYS Fluent. EDM solves conservation equations for chemical species by predicting local mass fractions through a convection-diffusion equation. Reaction rates are assumed to be controlled by turbulence, ignoring chemical timescales. EDM gives the smaller of two expressions to calculate reaction rates, with the chemical reaction rate governed by the large eddy mixing timescale. EDM is computationally cheap but works best for one-two step global reactions, as it cannot capture detailed chemistry effects.
01 reactive flows - governing equations favre averaging Mohammad Jadidi
油
This document discusses reactive flow modeling in combustion chambers. It covers the equations governing reacting flows, including conservation equations for mass, momentum, molecular species, and energy. It also discusses the equation of state and turbulence transport. The document then covers statistical descriptions of turbulent flows using Reynolds decomposition and Favre averaging. Favre averaging is preferred for reacting flows with variable density as it leads to simpler expressions in the transport equations for continuity, momentum, species, and energy compared to Reynolds averaging. Various terms that arise in the averaged equations require turbulence modeling approaches.
The document discusses the governing equations for reacting flows, including conservation of mass, momentum, molecular species, and energy. It outlines the continuity, momentum, species transport, and energy equations. The species transport equation accounts for convection, diffusion, and chemical reaction sources. The energy equation considers changes in enthalpy due to convection, diffusion, pressure work, and radiation. Simplifications are discussed under certain assumptions, such as a single diffusion coefficient and negligible pressure work/radiation terms, in which case enthalpy behaves as a passive scalar. Other relationships presented include the equation of state and definitions of specific heat capacity and density.
01 reactive flows - finite-rate formulation for reaction modelingMohammad Jadidi
油
This document discusses equations governing reacting flows as modeled in ANSYS Fluent. It describes how Fluent solves conservation equations for species mass fractions using a convection-diffusion equation, where the chemical source term Ri accounts for reaction rates. Finite-rate kinetics and turbulence-chemistry interaction models are discussed for determining Ri, including the eddy dissipation model. The Arrhenius equation is also presented for calculating forward reaction rate constants based on pre-exponential factors, temperature exponents, and activation energies specified in the kinetic mechanism.
The document discusses different types of multiphase flows. It defines multiphase flow as any fluid system with two or more distinct phases flowing simultaneously in mixture. Multiphase flows are classified into four main categories: gas-liquid flows, gas-solid flows, liquid-solid flows, and three-phase flows. Each category contains different flow regimes depending on factors like particle size and flow rates. Flow maps are used to characterize different flow patterns that can occur for a given system.
This document discusses turbulence modeling in computational fluid dynamics (CFD). It contains three main points:
1. Turbulence models used in CFD simulations like RANS and LES are introduced. Important turbulence concepts such as eddies, length scales, and the energy cascade are explained.
2. Reynolds-averaged Navier-Stokes (RANS) equations are presented along with Reynolds stress tensor and turbulent heat flux terms. Common RANS turbulence models and their governing equations are outlined.
3. Large eddy simulation (LES) is described as an alternative to RANS. Filtering operations in LES to separate large and small scales are discussed. Root-mean-square velocities are presented as a
Air pollution is contamination of the indoor or outdoor environment by any ch...dhanashree78
油
Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.
Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases and are important sources of morbidity and mortality.
WHO data show that almost all of the global population (99%) breathe air that exceeds WHO guideline limits and contains high levels of pollutants, with low- and middle-income countries suffering from the highest exposures.
Air quality is closely linked to the earths climate and ecosystems globally. Many of the drivers of air pollution (i.e. combustion of fossil fuels) are also sources of greenhouse gas emissions. Policies to reduce air pollution, therefore, offer a win-win strategy for both climate and health, lowering the burden of disease attributable to air pollution, as well as contributing to the near- and long-term mitigation of climate change.
The document discusses turbulence near walls and different approaches to modeling it in computational fluid dynamics (CFD). It explains that the boundary layer can be divided into different zones, and CFD requires different considerations depending on whether the viscous sub-layer is solved, the log-law layer is modeled, or the whole boundary layer is solved. It also discusses the use of non-dimensional variables to characterize the boundary layer and describes different near-wall treatments in CFD, including resolving the boundary layer with fine meshes or using wall functions with coarser meshes.
The document discusses reactive flow modeling using the eddy dissipation model (EDM) in ANSYS Fluent. EDM solves conservation equations for chemical species by predicting local mass fractions through a convection-diffusion equation. Reaction rates are assumed to be controlled by turbulence, ignoring chemical timescales. EDM gives the smaller of two expressions to calculate reaction rates, with the chemical reaction rate governed by the large eddy mixing timescale. EDM is computationally cheap but works best for one-two step global reactions, as it cannot capture detailed chemistry effects.
01 reactive flows - governing equations favre averaging Mohammad Jadidi
油
This document discusses reactive flow modeling in combustion chambers. It covers the equations governing reacting flows, including conservation equations for mass, momentum, molecular species, and energy. It also discusses the equation of state and turbulence transport. The document then covers statistical descriptions of turbulent flows using Reynolds decomposition and Favre averaging. Favre averaging is preferred for reacting flows with variable density as it leads to simpler expressions in the transport equations for continuity, momentum, species, and energy compared to Reynolds averaging. Various terms that arise in the averaged equations require turbulence modeling approaches.
The document discusses the governing equations for reacting flows, including conservation of mass, momentum, molecular species, and energy. It outlines the continuity, momentum, species transport, and energy equations. The species transport equation accounts for convection, diffusion, and chemical reaction sources. The energy equation considers changes in enthalpy due to convection, diffusion, pressure work, and radiation. Simplifications are discussed under certain assumptions, such as a single diffusion coefficient and negligible pressure work/radiation terms, in which case enthalpy behaves as a passive scalar. Other relationships presented include the equation of state and definitions of specific heat capacity and density.
01 reactive flows - finite-rate formulation for reaction modelingMohammad Jadidi
油
This document discusses equations governing reacting flows as modeled in ANSYS Fluent. It describes how Fluent solves conservation equations for species mass fractions using a convection-diffusion equation, where the chemical source term Ri accounts for reaction rates. Finite-rate kinetics and turbulence-chemistry interaction models are discussed for determining Ri, including the eddy dissipation model. The Arrhenius equation is also presented for calculating forward reaction rate constants based on pre-exponential factors, temperature exponents, and activation energies specified in the kinetic mechanism.
The document discusses different types of multiphase flows. It defines multiphase flow as any fluid system with two or more distinct phases flowing simultaneously in mixture. Multiphase flows are classified into four main categories: gas-liquid flows, gas-solid flows, liquid-solid flows, and three-phase flows. Each category contains different flow regimes depending on factors like particle size and flow rates. Flow maps are used to characterize different flow patterns that can occur for a given system.
This document discusses turbulence modeling in computational fluid dynamics (CFD). It contains three main points:
1. Turbulence models used in CFD simulations like RANS and LES are introduced. Important turbulence concepts such as eddies, length scales, and the energy cascade are explained.
2. Reynolds-averaged Navier-Stokes (RANS) equations are presented along with Reynolds stress tensor and turbulent heat flux terms. Common RANS turbulence models and their governing equations are outlined.
3. Large eddy simulation (LES) is described as an alternative to RANS. Filtering operations in LES to separate large and small scales are discussed. Root-mean-square velocities are presented as a
Air pollution is contamination of the indoor or outdoor environment by any ch...dhanashree78
油
Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.
Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution. Pollutants of major public health concern include particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. Outdoor and indoor air pollution cause respiratory and other diseases and are important sources of morbidity and mortality.
WHO data show that almost all of the global population (99%) breathe air that exceeds WHO guideline limits and contains high levels of pollutants, with low- and middle-income countries suffering from the highest exposures.
Air quality is closely linked to the earths climate and ecosystems globally. Many of the drivers of air pollution (i.e. combustion of fossil fuels) are also sources of greenhouse gas emissions. Policies to reduce air pollution, therefore, offer a win-win strategy for both climate and health, lowering the burden of disease attributable to air pollution, as well as contributing to the near- and long-term mitigation of climate change.
Best KNow Hydrogen Fuel Production in the World The cost in USD kwh for H2Daniel Donatelli
油
The cost in USD/kwh for H2
Daniel Donatelli
Secure Supplies Group
Index
Introduction - Page 3
The Need for Hydrogen Fueling - Page 5
Pure H2 Fueling Technology - Page 7
Blend Gas Fueling: A Transition Strategy - Page 10
Performance Metrics: H2 vs. Fossil Fuels - Page 12
Cost Analysis and Economic Viability - Page 15
Innovations Driving Leadership - Page 18
Laminar Flame Speed Adjustment
Heat Management Systems
The Donatelli Cycle
Non-Carnot Cycle Applications
Case Studies and Real-World Applications - Page 22
Conclusion: Secure Supplies Leadership in Hydrogen Fueling - Page 27
Engineering at Lovely Professional University (LPU).pdfSona
油
LPUs engineering programs provide students with the skills and knowledge to excel in the rapidly evolving tech industry, ensuring a bright and successful future. With world-class infrastructure, top-tier placements, and global exposure, LPU stands as a premier destination for aspiring engineers.
Lessons learned when managing MySQL in the CloudIgor Donchovski
油
Managing MySQL in the cloud introduces a new set of challenges compared to traditional on-premises setups, from ensuring optimal performance to handling unexpected outages. In this article, we delve into covering topics such as performance tuning, cost-effective scalability, and maintaining high availability. We also explore the importance of monitoring, automation, and best practices for disaster recovery to minimize downtime.
Optimization of Cumulative Energy, Exergy Consumption and Environmental Life ...J. Agricultural Machinery
油
Optimal use of resources, including energy, is one of the most important principles in modern and sustainable agricultural systems. Exergy analysis and life cycle assessment were used to study the efficient use of inputs, energy consumption reduction, and various environmental effects in the corn production system in Lorestan province, Iran. The required data were collected from farmers in Lorestan province using random sampling. The Cobb-Douglas equation and data envelopment analysis were utilized for modeling and optimizing cumulative energy and exergy consumption (CEnC and CExC) and devising strategies to mitigate the environmental impacts of corn production. The Cobb-Douglas equation results revealed that electricity, diesel fuel, and N-fertilizer were the major contributors to CExC in the corn production system. According to the Data Envelopment Analysis (DEA) results, the average efficiency of all farms in terms of CExC was 94.7% in the CCR model and 97.8% in the BCC model. Furthermore, the results indicated that there was excessive consumption of inputs, particularly potassium and phosphate fertilizers. By adopting more suitable methods based on DEA of efficient farmers, it was possible to save 6.47, 10.42, 7.40, 13.32, 31.29, 3.25, and 6.78% in the exergy consumption of diesel fuel, electricity, machinery, chemical fertilizers, biocides, seeds, and irrigation, respectively.
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Preface: The ReGenX Generator innovation operates with a US Patented Frequency Dependent Load Current Delay which delays the creation and storage of created Electromagnetic Field Energy around the exterior of the generator coil. The result is the created and Time Delayed Electromagnetic Field Energy performs any magnitude of Positive Electro-Mechanical Work at infinite efficiency on the generator's Rotating Magnetic Field, increasing its Kinetic Energy and increasing the Kinetic Energy of an EV or ICE Vehicle to any magnitude without requiring any Externally Supplied Input Energy. In Electricity Generation applications the ReGenX Generator innovation now allows all electricity to be generated at infinite efficiency requiring zero Input Energy, zero Input Energy Cost, while producing zero Greenhouse Gas Emissions, zero Air Pollution and zero Nuclear Waste during the Electricity Generation Phase. In Electric Motor operation the ReGen-X Quantum Motor now allows any magnitude of Work to be performed with zero Electric Input Energy.
Demonstration Protocol: The demonstration protocol involves three prototypes;
1. Protytpe #1, demonstrates the ReGenX Generator's Load Current Time Delay when compared to the instantaneous Load Current Sine Wave for a Conventional Generator Coil.
2. In the Conventional Faraday Generator operation the created Electromagnetic Field Energy performs Negative Work at infinite efficiency and it reduces the Kinetic Energy of the system.
3. The Magnitude of the Negative Work / System Kinetic Energy Reduction (in Joules) is equal to the Magnitude of the created Electromagnetic Field Energy (also in Joules).
4. When the Conventional Faraday Generator is placed On-Load, Negative Work is performed and the speed of the system decreases according to Lenz's Law of Induction.
5. In order to maintain the System Speed and the Electric Power magnitude to the Loads, additional Input Power must be supplied to the Prime Mover and additional Mechanical Input Power must be supplied to the Generator's Drive Shaft.
6. For example, if 100 Watts of Electric Power is delivered to the Load by the Faraday Generator, an additional >100 Watts of Mechanical Input Power must be supplied to the Generator's Drive Shaft by the Prime Mover.
7. If 1 MW of Electric Power is delivered to the Load by the Faraday Generator, an additional >1 MW Watts of Mechanical Input Power must be supplied to the Generator's Drive Shaft by the Prime Mover.
8. Generally speaking the ratio is 2 Watts of Mechanical Input Power to every 1 Watt of Electric Output Power generated.
9. The increase in Drive Shaft Mechanical Input Power is provided by the Prime Mover and the Input Energy Source which powers the Prime Mover.
10. In the Heins ReGenX Generator operation the created and Time Delayed Electromagnetic Field Energy performs Positive Work at infinite efficiency and it increases the Kinetic Energy of the system.